According to sources close to the situation, Flipboard has raised $50 million in new funding, in a round led by Rizvi Traverse Management and Goldman Sachs….In addition, sources said, current investors, including venture firms Kleiner Perkins and Index Ventures, are also participating, while Insight Venture Partners is taking an even larger stake in Flipboard.

Flipboard’s last round of funding was in mid-2011, when it raised $50 million at a $200 million valuation. That came after a $10.5 million initial round.

The valuation of Flipboard is an example of a Silicon Valley media company that produces no media content of its own. Its revenues come from advertising placed on its app which collects content recommended by the social networks of its users. Its revenues are not disclosed and it employs less than 200 people.

The New York Times Company [$NYT] publishes two national newspapers plus 16 regional newspapers. It also owns eight television stations and two New York radio stations. It operates more than 40 web sites. It has 5,363 staff and 2012 revenues of $2 billion.

Clearly, if you have to pay for your content you are at a significant disadvantage in the new media industry as the valuation of Flipboard demonstrates.